1. Field of the Invention
The present invention relates to a composition for an anti-reflective coating composition, which is effective in reducing the adverse effect of the reflection from the background substrate, and to a method for forming a photoresist pattern using this composition for an anti-reflective coating.
2. Description of the Prior Art
The fine processing with lithography using the photoresist composition has been conducted for the preparation of semiconductor device heretofore. Said fine processing is the processing method comprising forming a film of the photoresist composition over silicon wafer, irradiating active light rays such as UV light through the mask pattern over which the pattern of semiconductor device has been drawn, developing and executing the etching treatment of silicon wafer of thus obtained photoresist pattern as the protective film. However, the higher degree of integration of semiconductor device has been achieved in recent years and active light rays used show tendency toward preferring short wave length from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). Along with this progress, effects of irregular reflection and standing wave of active light rays from the substrate have become the major concern. Therefore, the method of providing the Bottom anti-reflective coating between the photoresist and the substrate has been extensively investigated.
Inorganic bottom anti-reflective coating made of such as titanium, titanium dioxide, titanium nitride, chrome oxide, carbon, α-silicon and the like, and organic bottom anti-reflective coating made of light absorbing material and polymer compound as the bottom anti-reflective coating are known. The former requires facilities such as vacuum deposition equipment, CVD device, spattering device and the like, while the latter is advantageous since the latter does not require any special facilities and therefore various investigations have been conducted. Example of as such are acrylic resin type bottom anti-reflective coating with hydroxyl group as crosslinking forming functional group and light absorbing group in the same molecule disclosed in U.S. Pat. No. 5,919,599 and novolac resin type bottom anti-reflective coating with hydroxyl group as crosslinking forming functional group and light absorbing group in the same molecule described in U.S. Pat. No. 5,693,691 among others.
The desirable physical properties for the organic type bottom anti-reflective coating materials are having high absorbance against light or irradiation rays, absence of intermixing with photoresist layer (insoluble in resist solvent), no diffusion of small molecule into overcoating resist from the bottom anti-reflective coating material when applied or dried with heating, having large dry etching rate in comparison with resist and the like, and these are also described in for example Proc. SPIE, Vol. 3678, 174-185 (1999), Proc. SPIE, Vol. 3678, 800-809 (1999), Proc. SPIE, Vol. 2195, 225-229 (1994).
Along with the progress of resist pattern scale miniaturization, the thinner photoresist film is to be used. Therefore, it is needed to cut largely the time of organic bottom anti-reflective coating etching removal process, and an organic bottom anti-reflective coating which is usable at thinner thickness than ever before or which has bigger etching selectivity in comparison to photoresist than ever before has become required.
U.S. Pat. No. 5,756,255, No. 5,948,847, No. 6,284,428 and No. 2002/0055064 disclose anti-reflective coating compositions comprising triazine compounds.